在CAD 命令中画多段线的命令为：pline。下面将介绍一种JIG画多段线的方法。

首先，来介绍一下JIG这个东西。

EntityJig(实体动态预览)，按照指定步骤模仿特定类型的单个实体对象。首先，定义一个类，该类继承于： Autodesk.AutoCAD.EditorInput.EntityJig。继承该类后，需要重写两个方法。 protected override SamplerStatus Sampler(JigPrompts prompts)和  protected override bool Update()这两个方法。

与正常的Prompt一样需要处理JIG的Prompt。

在Sampler方法中编写如下代码：处理提示消息。并获得用户输入信息

JigPromptPointOptions jigOpts = new JigPromptPointOptions();

jigOpts.UserInputControls = (UserInputControls.Accept3dCoordinates |

UserInputControls.NullResponseAccepted |

UserInputControls.NoNegativeResponseAccepted);

在Update方法中更新每一次的拖拽。

完整代码如下：

public class ClsDrawJigLine : Autodesk.AutoCAD.EditorInput.EntityJig

{

#region 成员变量

public static int color = 0;

public static Point3dCollection m_pts;

Point3d m_tempPoint;

Plane m_plane;

#endregion

#region 构造方法

public ClsDrawJigLine(Matrix3d ucs)

: base(new Polyline())

{

m_pts = new Point3dCollection();

Point3d origin = new Point3d(0, 0, 0);

Vector3d normal = new Vector3d(0, 0, 1);

normal = normal.TransformBy(ucs);

m_plane = new Plane(origin, normal);

Polyline pline = Entity as Polyline;

pline.SetDatabaseDefaults();

pline.Normal = normal;

pline.ColorIndex = color;

pline.AddVertexAt(0, new Point2d(0, 0), 0, 0, 0);

}

#endregion

/// /// 画线

///

///

///

public Point3dCollection DragLine(int colorIndex)

{

return ClsDrawJigLine.PolyJig(colorIndex);

}

#region 画线方法

/// /// 画线

///

/// 颜色

///

public static Point3dCollection PolyJig(int colorIndex)

{

color = colorIndex;

Document doc = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument;

Editor ed = Autodesk.AutoCAD.ApplicationServices.Application.DocumentManager.MdiActiveDocument.Editor;

Matrix3d ucs = ed.CurrentUserCoordinateSystem;

ClsDrawJigLine jig = new ClsDrawJigLine(ucs);

bool bSuccess = true, bComplete = false;

do

{

PromptResult res = ed.Drag(jig);

bSuccess = (res.Status == PromptStatus.OK);

if (bSuccess)

jig.AddLatestVertex();

if (res.Status != PromptStatus.OK)

{

Confirm frm = new Confirm();

frm.ShowDialog();

Confirm.Operate operateType = frm._operrateType;

switch (operateType)

{

case Confirm.Operate.Continue:

bSuccess = true;

bComplete = false;

break;

case Confirm.Operate.Back:

if (m_pts.Count > 0)

{

m_pts.RemoveAt(m_pts.Count - 1);

bSuccess = true;

bComplete = false;

jig.RemoveLastVertex();

}

break;

case Confirm.Operate.Accept:

break;

}

}

} while (bSuccess && !bComplete);

return m_pts;

}

#endregion

#region 用于在完成Drag后，移除最后个虚构的点

/// /// 用于在完成Drag后，移除最后个虚构的点

///

public void RemoveLastVertex()

{

Polyline pline = Entity as Polyline;

if (pline.NumberOfVertices > 1)

{

pline.RemoveVertexAt(m_pts.Count);

}

}

#endregion

#region 在添加一个点时激发事件

/// /// 事件委托

///

/// 事件参数

public delegate void AddHandle(EventArgs e);

public class EventArgs

{

public EventArgs(Point3dCollection currentPoints, int index)

{

this.currentPoints = currentPoints;

this.index = index;

}

/// /// 当前点集合

///

private Point3dCollection currentPoints;

/// /// 当前点集合

///

public Point3dCollection CurrentPoints

{

get { return currentPoints; }

}

/// /// 当前点索引

///

private int index;

/// /// 当前点索引

///

public int Index

{

get { return index; }

}

/// /// 是否取消点绘制

///

private bool isCancel = false;

/// /// 是否取消点绘制

///

public bool IsCancel

{

get { return isCancel; }

set { isCancel = value; }

}

}

/// /// 添加一个点时激发事件

///

public static event AddHandle AddPoint;

#endregion

#region 总是设置polyline为一个虚构的点，在完成Drag后，此点会被移除

/// /// 总是设置polyline为一个虚构的点，在完成Drag后，此点会被移除

///

public void AddLatestVertex()

{

m_pts.Add(m_tempPoint);

Polyline pline = Entity as Polyline;

pline.AddVertexAt(pline.NumberOfVertices, new Point2d(m_tempPoint.X, m_tempPoint.Y), 0, 0, 0);

if (AddPoint != null)

{

EventArgs e = new EventArgs(m_pts, m_pts.Count - 1);

e.IsCancel = false;

AddPoint(e);

if (e.IsCancel)

{

RemoveLastVertex();

}

}

}

#endregion

#region 取样

/// /// 取样

///

///

///

protected override SamplerStatus Sampler(JigPrompts prompts)

{

JigPromptPointOptions jigOpts = new JigPromptPointOptions();

jigOpts.UserInputControls = (UserInputControls.Accept3dCoordinates |

UserInputControls.NullResponseAccepted |

UserInputControls.NoNegativeResponseAccepted);

if (m_pts.Count == 0)

{

jigOpts.Message = "\n请输入起点坐标 ";

}

else if (m_pts.Count > 0)

{

jigOpts.BasePoint = m_pts[m_pts.Count - 1];

jigOpts.UseBasePoint = true;

jigOpts.Message = "\n请输入下一个点[或按ESC退出] ";

}

else

return SamplerStatus.Cancel;

PromptPointResult res = prompts.AcquirePoint(jigOpts);

if (m_tempPoint == res.Value)

{

return SamplerStatus.NoChange;

}

else if (res.Status == PromptStatus.OK)

{

m_tempPoint = res.Value;

return SamplerStatus.OK;

}

return SamplerStatus.Cancel;

}

#endregion

#region 更新

/// /// 更新

///

///

protected override bool Update()

{

Polyline pline = Entity as Polyline;

pline.SetPointAt(pline.NumberOfVertices - 1, m_tempPoint.Convert2d(m_plane));

Matrix3d m = Matrix3d.Displacement(new Vector3d(0, 0, 1000));

pline.TransformBy(m);

return true;

}

#endregion

}

其中confirm是一个窗体。用来和用户交互信息，实现交互操作

后台代码为：

/// ///

public partial class Confirm : Form

{

/// ///

// ARXClass _aRXClass = null;

#region 构造方法

/// /// 构造方法

///

public Confirm()

{

//    _aRXClass = new ARXClass();

InitializeComponent();

}

#endregion

#region 操作类型

/// /// 操作类型

///

public enum Operate

{

/// /// 继续

///

Continue = 0,

/// /// 后退

///

Back = 1,

/// /// 确定

///

Accept = 2

}

#endregion

#region 类成员

/// /// 类成员

///

public Operate _operrateType = Operate.Continue;

#endregion

#region 点击继续按钮激发事件

/// /// 点击继续按钮激发事件

///

private void btnContinue_Click(object sender, EventArgs e)

{

this._operrateType = Operate.Continue;

this.Close();

}

#endregion

#region 点击回退按钮激发事件

/// /// 点击回退按钮激发事件

///

private void btnBack_Click(object sender, EventArgs e)

{

this._operrateType = Operate.Back;

this.Close();

}

#endregion

#region 点击确定按钮激发事件

/// /// 点击确定按钮激发事件

///

private void btnAccept_Click(object sender, EventArgs e)

{

// 确定

this._operrateType = Operate.Accept;

// 关闭窗体

this.Close();

}

#endregion

}

以上方法仅供参考。

若各位大侠手里有更好的方法，请顺便贴一下，谢谢。

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